Abstract Tracheobonchomalacia (TBM) is a congenital or acquired deficiency of tracheal and/or bronchial cartilages that presents with dynamic airway collapse, respiratory difficulties, and, in severe cases, acute life-threatening events. TBM prevalence is estimated at 1 in 2,200 children1, and severe cases can result in death or require tracheostomy with ventilation for 2-3 years, a significant burden on the child and family2,3. We recently developed a bioresorbable, patient specific 3D printed polycaprolactone (PCL) splint to treat TBM, reporting the first case in the New England J. of Medicine4. Three subsequent children with life threatening TBM were saved with the splint and the first child continues to be asymptomatic 30 months post-surgery. However, long term clinical application of the splint requires further engineering to reduce the risk of fatigue failure in addition to understanding how resorption of the splint affects mechanical deformation and remodeling of the airway to improve safety and efficacy of the splint. In addition, the FDA also requires such data for regulatory approval based on our August 22, 2014 meeting with the FDA to initiate a phase I clinical trial for Humanitarian Device Exempt (HDE) approval. We will address these questions in two specific aims using both in vitro and in vivo preclinical model, the Yorkshire pig. The first aim will characterize splint degradation both in vitro and in vivo for up to 2 years. The second aim will use this data to characterize how the splint affects airway mechanics.